Hi Janet, depending on the quantity of add-ins, they can certainly weight the dough down! Additional ingredients also tend to make it more difficult to develop the gluten structure because they act as obstacles, which can also lead to a denser structure. My preference when adding additonal ingredients is to do so after I've developed a fair amount of dough strength through kneading, so I'll often gently work them in at the end of the kneading process. This is obviously a bit more tricky when you're making a no-knead recipe, although the dough will likely incorporate the ingredients into the structure if given enough time. When I add olives I drain and rinse them, and then pat them dry so that I'm not adding too much excess liquid. If you find the additional ingredients you're using are adding a lot of extra moisture to your bread, you might want to try holding back on a small portion of the dough liquid. Check out Martin's blog post for more tips on changing up your favorite bread recipe. 

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